Gas phase infrared spectra of SO2 clusters and quantum chemical calculations of some stable isomers

We have observed infrared spectra of the SO2 clusters in gas phase for the first time by cavity ring-down spectroscopy, and assigned absorption bands of dimer and larger clusters in the OSO asymmetric stretching region. An analysis of the rotational contour showed that the dimeric band can be assigned to the SO2 vibration in an electron-donor side of the Cs-isomer of (SO2)2 observed by Fourier-transform microwave spectroscopy [A. Taleb-Bendiab et al., J. Chem. Phys. 94 (1991) 6956.]. The observed band type and wavenumber shift from monomer was consistent with the results of quantum chemical calculations.